"Human beings will naturally walk, sprint or run," he told Reuters. "Walking is a heel strike, running is a forefoot strike. Jogging is not a slow run. Jogging is actually a different biomechanical behaviour, a hybrid between a walk and a run. Distance runners never land on their heels."

According to Saxby, the three most important things to think about when jogging are keeping a good posture, having a bouncing, elastic rhythm and making sure your forefoot lands first.

Dr Mark Cucuzzella, associate professor of family medicine at West Virginia University in the US, agrees.

"So if you land on your fore and mid-foot you use the recoil aspect of the foot, which is designed to return energy," he told Reuters.

"The benefits of a daily walk or jog are enormous, but we need to teach people good mechanics, which is not landing hard on the heel."

According to Health & Wellbeing fitness expert Dean Piazza, also wearing the worn-out shoes can lead to injury. "If your shoes are more than six to eight months old I suggest getting a new pair of running shoes," he said.

"Not only does it motivate you to train more  it also gives you a lot more 'bounce' as you step. Running shoes start to lose their shock absorption qualities after about six months. So while they can still look new, they won't be as comfortable or as kind on your joints."